"Iwa-taigeki" (Euphorbia jolkinii) belongs to Euphorbiaceae (the Spurge family). It is a perennial herb that is native westward from Kanto district of Honshu to Shikoku, Kyushu of Japan, as well as Taiwan, the southern Korean Peninsula and southern China. This herb grows in coastal rocky places and mountain slopes, and can reach 30-50 cm in height. The leaves are ovate-olbong to elliptic, fleshy and arranged in alternate. The cyathia are borne on the yellow bracts from March to May.